2013.01.07科学家发现母亲的脑子里生长着孩子的细胞

1、2013.01.07科学家发现母亲的脑子里生长着孩子的细胞科学家发现母亲的脑子里生长着孩子的细胞Theconnectionbetweenmotherandchildiseverdeeperthanthought母亲和孩子的关系比所认为的还要深厚Alivingconnection生动的关联Thelinkbetweenamotherandchildisprofound,andnewresearchsuggestsaphysicalconnectionevendeeperthananyonethought.Theprofoundpsychologicalandphysicalbondssharedb

2、ythemotherandherchildbeginduringgestationwhenthemotheriseverythingforthedevelopingfetus,supplyingwarmthandsustenance,whileherheartbeatprovidesasoothingconstantrhythm.母亲和孩子之间的关联是很深厚的，新的研究提出了一种身体上的联系，这种联系比任何人所认为的都还要更深厚一些。母亲和孩子之间心理和身体上的亲密关系从怀孕的时候就开始了，那时母亲对发育中的胎儿来说意味着一切：提供温暖和营养，母亲固定频率的心跳对胎儿来说是一种抚慰。Theph

3、ysicalconnectionbetweenmotherandfetusisprovidedbytheplacenta,anorgan,builtofcellsfromboththemotherandfetus,whichservesasaconduitfortheofnutrients,gasses,andwastes.Cellsmaymigratethroughtheplacentabetweenthemotherandthefetus,takingupresidenceinmanyorgansofthebodyincludingthelung,thyroidmuscle,liver,h

4、eart,kidneyandskin.Thesemayhaveabroadrangeofimpacts,fromtissuerepairandcancerpreventiontosparkingimmunedisorders.母亲和胎儿的身体联系通过一个叫胎盘的器官，由来自母亲和胎儿的细胞组成，作为养料、气体和废物的交换通道。细胞可以通过胎盘在母亲和胎儿之间移动，可以留在身体的许多器官里面，包括肺、甲状腺肌肉、肝、心、肾以及皮肤。这些可以产生广泛的影响，从组织修复、癌症预防到引起免疫紊乱。Itisremarkablethatitissocommonforcellsfromoneindividu

5、altointegrateintothetissuesofanotherdistinctperson.Weareaccustomedtothinkingofourselvesassingularautonomousindividuals,andtheseforeigncellsseemtobeliethatnotion,andsuggestthatmostpeoplecarryremnantsofotherindividuals.Asremarkableasthismaybe,stunningresultsfromanewstudyshowthatcellsfromotherindividua

6、lsarealsofoundinthebrain.Inthisstudy,malecellswerefoundinthebrainsofwomenandhadbeenlivingthere,insomecases,forseveraldecades.Whatimpacttheymayhavehadisnowonlyaguess,butthisstudyrevealedthatthesecellswerelesscommoninthebrainsofwomenwhohadAlzheimersdisease,suggestingtheymayberelatedtothehealthofthebra

7、in.对细胞来说从一个个体进入到另外一个完全不同的个体中并结合在一起是很常见的，这一点太了不起了。我们习惯认为自己是独一无二的个体，这些外来的细胞好像与这个观点不符，而且表明了大部分人都携带着其他人的遗留痕迹。这一点或许很值得注意，一项新研究的结果则更让人大吃一惊，研究结果表明来自其他个体的细胞也在脑子里发现了。在这项研究中，男性的细胞在女性的脑子里面发现了，而且这些细胞在某些情况下可以在那里生存几十年。这些细胞究竟有何影响目前还仅是猜测，但是这项研究显示那些细胞在患有老年痴呆症的女性脑子里没有那么常见，暗示那些细胞可能和脑部健康有关系。Weallconsiderourbodiestobeou

8、rownuniquebeing,sothenotionthatwemayharborcellsfromotherpeopleinourbodiesseemsstrange.Evenstrangeristhethoughtthat,althoughwecertainlyconsiderouractionsanddecisionsasoriginatingintheactivityofourownindividualbrains,cellsfromotherindividualsarelivingandfunctioninginthatcomplexstructure.However,themix

9、ingofcellsfromgeneticallydistinctindividualsisnotatalluncommon.Thisconditioniscalledchimerismafterthefire-breathingChimerafromGreekmythology,acreaturethatwaspartserpentpartlionandpartgoat.Naturallyoccurringchimerasarefarlessominousthough,andincludesuchcreaturesastheslimemoldandcorals.我们都认为自己的身体是独一无二

10、的，所以我们的身体里含有来自别人的细胞这一概念好像很奇怪。更为奇怪的是这样一个想法：尽管我们很确定地认定我们的行为和决定源自我们个人脑子的活动，来自其他个体的细胞却在那个复杂的组织中存在并且发挥着作用。然而，来自基因截然不同的个体的细胞混合却一点也不罕见。这种情况被称为奇美拉现象，是以希腊神话中的吐火怪物喀迈拉而命名的，喀迈拉是一只狮头、羊身、蛇尾的怪物。可是，自然存在的那些喀迈拉们没有那么不吉利，包括一些像粘液菌和珊瑚虫的生物体。Microchimerismisthepersistentpresenceofafewgeneticallydistinctcellsinanorganism.Th

11、iswasfirstnoticedinhumansmanyyearsagowhencellscontainingthemale“Ychromosomewerefoundcirculatinginthebloodofwomenafterpregnancy.Sincethesecellsaregeneticallymale,theycouldnothavebeenthewomensown,butmostlikelycamefromtheirbabiesduringgestation.嵌合现象是指在一个有机体中持续存在着几种不同基因的细胞。很多年前首先在人体中发现，当时发现了包含男性染色体的细胞在怀

12、孕女性的血液中循环流通。既然这些细胞从遗传学上来说是男性的，它们就不可能是女人们自己的细胞，而极有可能是在怀孕期间从她们的胎儿中来的。Inthisnewstudy,scientistsobservedthatmicrochimericcellsarenotonlyfoundcirculatingintheblood,theyarealsoembeddedinthebrain.Theyexaminedthebrainsofdeceasedwomenforthepresenceofcellscontainingthemale“Y”chromosomTeh.eyfoundsuchcellsinmor

13、ethan60percentofthebrainsandinmultiplebrainregions.SinceAlzheimersdiseaseismorecommoninwomenwhohavehadmultiplepregnancies,theysuspectedthatthenumberoffetalcellswouldbegreaterinwomenwithADcomparedtothosewhohadnoevidenceforneurologicaldisease.Theresultswerepreciselytheopposite:therewerefewerfetal-deri

14、vedcellsinwomenwithAlzheimers.Thereasonsareunclear.在这项新研究中，科学家们观察到嵌合性细胞不但在血液中流通，而且还嵌入到了脑子里。他们检查了一些已故女士的脑部，查看是否有包含男性染色体的细胞存在。他们发现脑部有60%多的地方有这种细胞，而且分部在不同的脑部分区里。因为老年痴呆症在多次怀孕的女性身上更为常见，他们怀疑：患老年痴呆症的女性与那些没有神经疾病迹象的女性相比，胎儿细胞的含量要更大一些。结果却正好相反：患老年痴呆症的女性拥有的源于胎儿的细胞更少。原因尚不明了。Microchimerismmostcommonlyresultsfromth

15、eexchangeofcellsacrosstheplacentaduringpregnancy,howeverthereisalsoevidencethatcellsmaybetransferredfrommothertoinfantthroughnursing.Inadditiontoexchangebetweenmotherandfetus,theremaybeexchangeofcellsbetweentwinsinutero,andthereisalsothepossibilitythatcellsfromanoldersiblingresidinginthemothermayfin

16、dtheirwaybackacrosstheplacentatoayoungersiblingduringthelattersgestation.Womenmayhavemicrochimericcellsbothfromtheirmotheraswellasfromtheirownpregnancies,andthereisevenevidenceforcompetitionbetweencellsfromgrandmotherandinfantwithinthemother.嵌合现象最常见的是在怀孕期间细胞通过胎盘交换产生的，然而也有迹象表明细胞可能在喂奶的时候从母亲转移到孩子。除了母亲和

17、胎儿的交换之外，细胞的交换还可能在子宫里面的双胞胎之间产生，还有可能哥哥或者姐姐留在母亲体内的细胞在母亲后来怀孕期间通过胎盘转到小胎儿身上。女性的嵌合细胞可能来自她们的母亲也可能来自自己的怀孕，甚至有迹象表明母亲体内存在来自外祖母和婴儿细胞的竞争。Whatitisthatfetalmicrochimericcellsdointhemothersbodyisuncle,aralthoughtherearesomeintriguingpossibilities.Forexample,fetalmicrochimericcellsaresimilartostemcellsinthattheyarea

18、bletobecomeavarietyofdifferenttissuesandmayaidintissuerepair.Oneresearchgroupinvestigatingthispossibilityfollowedtheactivityoffetalmicrochimericcellsinamotherratafterthematernalheartwasinjured:theydiscoveredthatthefetalcellsmigratedtothematernalheartanddifferentiatedintoheartcellshelpingtorepairthed

19、amage.Inanimalstudies,microchimericcellswerefoundinmaternalbrainswheretheybecamenervecells,suggestingtheymightbefunctionallyintegratedinthebrain.Itispossiblethatthesamemaytrueofsuchcellsinthehumanbrain.胎儿的嵌合细胞到底在母亲体内做些什么还不清楚，虽然有一些可能性很吸引人。比如，胎儿的嵌合细胞在那些类似的干细胞里能变成很多种不同的组织，可以帮助组织修护。一个研究小组对这一可能性进行了调查在一只老

20、鼠妈妈的心脏受伤以后跟踪调查了胎儿嵌合细胞在老鼠妈妈体内的活动：他们发现胎儿细胞移到了母体心脏那里，并且分化成了心脏细胞帮助修复损害。在动物研究中，在母体脑部发现了嵌合细胞，在那里它们变成了神经细胞，显示它们可能融入到了脑部官能中。这类细胞在人脑也可能是这样的。Thesemicrochimericcellsmayalsoinfluencetheimmunesystem.Afetalmicrochimericcellfromapregnancyisrecognizedbythemothersimmunesystempartlyasbelongingtothemother,sincethefetu

21、sisgeneticallyhalfidenticaltothemother,butpartlyforeign,duetothefathersgeneticcontribution.Thismay“prime”theimmunesystemtobealertforcellsthataresimilartotheself,butwithsomegeneticdifferences.Cancercellswhichariseduetogeneticmutationsarejustsuchcells,andtherearestudieswhichsuggestthatmicrochimericcel

22、lsmaystimulatetheimmunesystemtostemthegrowthoftumors.Manymoremicrochimericcellsarefoundinthebloodofhealthywomencomparedtothosewithbreastcancer,forexample,suggestingthatmicrochimericcellscansomehowpreventtumorformation.Inothercircumstances,theimmunesystemturnsagainsttheself,causingsignificantdamage.Micr